Composite film and packaging material of polypropylene base and surface polymer composition
US4343852A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 14, 1980 |
| Grant date | Aug 10, 1982 |
| Priority date | — |
| Expiry date | Jul 14, 2000 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31971
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A packaging material which is capable of packaging an article(s) in a closely fitted and tightly sealed state and consists essentially of a composite film stretched at least in one direction, PA1 said composite film comprising a base film and a surface film provided on at least one surface of the base film and having certain specific shrinkage characteristics, PA2 said base film being made of a resin composition comprising a propylene polymer, and PA2 said surface film being made of a polymer composition comprising at least two of (A) a copolymer of propylene and ethylene in a weight proportion of 99.5:0.5 to 90:10, (B) a copolymer of propylene and an .alpha.-olefin having 4 to 10 carbon atoms in a weight proportion of 70:30 to 95:5 and (C) a copolymer of butene and any other .alpha.-olefin having 2 to 10 carbon atoms in a weight proportion of 70:30 to 99:1, each of the copolymers being in an amount of 10 to 90% by weight on the total weight of the copolymers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.